Dental x-ray unit



FIG. 1 is a perspective view of an embodiment of our ornamental design for a dental X-ray unit;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a side elevational view thereof;

FIG. 4 is a side elevational view thereof from the opposite side; and,

FIG. 5 is a top plan view thereof. 

The ornamental design for a dental X-ray unit, substantially as shown and described. 